The invention relates to a profile rail joint for use for example in light crane systems, the joint comprising connecting ends of profile rails to be joined, provided with jointing sleeves arranged on side surfaces of the rails, the sleeves comprising through holes for locking means of the joint, and at least two of the sleeves being situated in profile recesses of the rails, the joint further comprising guide elements extending over the joint surface for aligning the connecting ends.
Swedish Patent 505,892 discloses a substantially similar profile joint as described above. In this publication, control means consist of interacting guide surfaces, such as conical male and female surfaces, provided at the ends of jointing sleeves of the profile rails to be arranged one against the other. This Swedish Patent also discloses a separate annular guide element provided between the ends of the jointing sleeves, and the guide surfaces are arranged between the end of the sleeve and the end of the guide element.
The aforementioned Swedish Patent does not describe in greater detail the formation of the guide surfaces. In fact, interacting guide surfaces cannot be formed in a joint that is made without a separate connecting piece, at least not after the jointing sleeves have already been mounted in place at the ends of the rail. For example, it is virtually impossible to form afterwards a male cone that would protrude from the joint surface, let alone other possible shapes of the guide surface. Therefore the guide surfaces must be formed in the sleeves before they are welded in place. Unless the sleeves are exactly aligned, it is also likely that only conical guide surfaces will work satisfactorily. On the other hand, the use of separate connecting pieces requires four guide surface to be provided in each joint surface to be arranged against another surface. This, in turn, requires a great deal of work and accuracy. Furthermore, separate short connecting pieces tend to fall off when a joint is being made.
U.S. Pat. No. 5,400,717 discloses a connection arrangement comprising welded alignment bushings and aligning pins inserted into the bushings to achieve proper alignment of the connection. However, the bushings are not used, nor can they be used to provide lead-throughs for fastening bolts or, in general, to tighten the connection. To form a connection, the lateral surfaces of the profiles are provided with separate fastening flanges.
U.S. Pat. No. 5,443,151 discloses a similar arrangement as described above, but alignment grooves corresponding to the alignment bushings are provided in an aluminium alloy profile already during the manufacture thereof and not afterwards through welding, as in the case of the alignment bushings. Also in this patent, the alignment grooves are entirely separate from the fastening bolts, since here, too, the fastening means are mounted afterwards in web sections of the profiles.